Method for whitening tobacco

ABSTRACT

A method of preparing a whitened tobacco material is provided, the method including the steps of (i) extracting a tobacco material with an aqueous solution to give a tobacco solids material and a tobacco extract; (ii) treating the tobacco solids material with a caustic wash to give a tobacco pulp; (iii) bleaching the tobacco pulp with a solution including a strong base, an oxidizing agent, or a combination thereof to give a bleached tobacco pulp; and (iv) drying the bleached tobacco pulp to give the whitened tobacco material. The invention also provides a smokeless tobacco product incorporating a whitened tobacco material. The smokeless tobacco product may be a snus-type formulation contained within a sealed pouch.

FIELD OF THE INVENTION

The present invention relates to products made or derived from tobacco, or that otherwise incorporate tobacco, and are intended for human consumption.

BACKGROUND

Cigarettes, cigars and pipes are popular smoking articles that employ tobacco in various forms. Such smoking articles are used by heating or burning tobacco, and aerosol (e.g., smoke) is inhaled by the smoker. Tobacco also may be enjoyed in a so-called “smokeless” form. Particularly popular smokeless tobacco products are employed by inserting some form of processed tobacco or tobacco-containing formulation into the mouth of the user.

Various types of smokeless tobacco products are known. See for example, the types of smokeless tobacco formulations, ingredients, and processing methodologies set forth in U.S. Pat. No. 1,376,586 to Schwartz; U.S. Pat. No. 3,696,917 to Levi; U.S. Pat. No. 4,513,756 to Pittman et al.; U.S. Pat. No. 4,528,993 to Sensabaugh, Jr. et al.; U.S. Pat. No. 4,624,269 to Story et al.; U.S. Pat. No. 4,991,599 to Tibbetts; U.S. Pat. No. 4,987,907 to Townsend; U.S. Pat. No. 5,092,352 to Sprinkle, III et al.; U.S. Pat. No. 5,387,416 to White et al.; U.S. Pat. No. 6,668,839 to Williams; U.S. Pat. No. 6,834,654 to Williams; U.S. Pat. No. 6,953,040 to Atchley et al.; U.S. Pat. No. 7,032,601 to Atchley et al.; and U.S. Pat. No. 7,694,686 to Atchley et al.; US Pat. Pub. Nos. 2004/0020503 to Williams; 2005/0115580 to Quinter et al.; 2006/0191548 to Strickland et al.; 2007/0062549 to Holton, Jr. et al.; 2007/0186941 to Holton, Jr. et al.; 2007/0186942 to Strickland et al.; 2008/0029110 to Dube et al.; 2008/0029116 to Robinson et al.; 2008/0173317 to Robinson et al.; 2008/0196730 to Engstrom et al.; 2008/0209586 to Neilsen et al.; 2008/0305216 to Crawford et al.; 2009/0065013 to Essen et al.; 2009/0293889 to Kumar et al.; 2010/0291245 to Gao et al; and 2011/0139164 to Mua et al.; PCT WO 04/095959 to Arnarp et al. and WO 2010/132444 to Atchley; each of which is incorporated herein by reference.

One type of smokeless tobacco product is referred to as “snuff.” Representative types of moist snuff products, commonly referred to as “snus,” are manufactured in Europe, particularly in Sweden, by or through companies such as Swedish Match AB, Fiedler & Lundgren AB, Gustavus AB, Skandinavisk Tobakskompagni A/S, and Rocker Production AB. Smokeless tobacco products available in the U.S.A. are marketed under the tradenames CAMEL Snus, CAMEL Orbs, CAMEL Strips and CAMEL Sticks by R. J. Reynolds Tobacco Company; GRIZZLY moist tobacco, KODIAK moist tobacco, LEVI GARRETT loose tobacco and TAYLOR'S PRIDE loose tobacco by American Snuff Company, LLC; KAYAK moist snuff and CHATTANOOGA CHEW chewing tobacco by Swisher International, Inc.; REDMAN chewing tobacco by Pinkerton Tobacco Co. LP; COPENHAGEN moist tobacco, COPENHAGEN Pouches, SKOAL Bandits, SKOAL Pouches, RED SEAL long cut and REVEL Mint Tobacco Packs by U.S. Smokeless Tobacco Company; and MARLBORO Snus and Taboka by Philip Morris USA. See also, for example, Bryzgalov et al., 1N1800 Life Cycle Assessment, Comparative Life Cycle Assessment of General Loose and Portion Snus (2005). In addition, certain quality standards associated with snus manufacture have been assembled as a so-called GothiaTek standard.

Through the years, various treatment methods and additives have been proposed for altering the overall character or nature of tobacco materials utilized in tobacco compositions. For example, additives or treatment processes are sometimes utilized in order to alter the chemistry or sensory properties of the tobacco material, or in the case of smokable tobacco materials, to alter the chemistry or sensory properties of mainstream smoke generated by smoking articles including the tobacco material. In some cases, a heat treatment process can be used to impart a desired color or visual character to the tobacco material, desired sensory properties to the tobacco material, or a desired physical nature or texture to the tobacco material.

It would be desirable in the art to provide further methods for altering the character and nature of tobacco (and tobacco compositions and formulations) useful in smoking articles or smokeless tobacco products.

BRIEF SUMMARY

The present disclosure provides a method of processing a tobacco material to modify the color of the tobacco material, specifically to provide a tobacco material that is lightened in color (i.e., “whitened”). The whitened tobacco material can be used in smokeless tobacco materials to give materials adapted for oral use with a whitened appearance.

In various embodiments of preparing a whitened tobacco material described herein, the method can include (i) extracting a tobacco material with an aqueous solution to provide a tobacco solids material and a tobacco extract; (ii) treating the tobacco solids material with a caustic wash to provide a tobacco pulp; (iii) bleaching the tobacco pulp with a solution comprising a strong base, an oxidizing agent, or a combination thereof to provide a bleached tobacco pulp; and (iv) drying the bleached tobacco pulp to provide the whitened tobacco material. In certain embodiments, the bleached tobacco pulp can be dried to a moisture content of less than about 30 percent moisture on a wet basis. In various embodiments, the whitened tobacco material is characterized by an International Organization for Standardization (ISO) brightness of at least about 55%, at least about 60%, at least about 65%, or at least about 70%.

In certain embodiments, the tobacco input material comprises lamina, stems, or a combination thereof. For example, the tobacco input material can include Rustica stems and/or Burley stems. In some embodiments, the tobacco input material comprises at least about 90% by weight roots, stalks, or a combination thereof.

The method can further include milling the tobacco material before the extraction step such that the milled tobacco material is able to pass through a screen of 18 or 16 U.S. sieve size. In some embodiments, the method can further include hydrolyzing the tobacco pulp with an acid prior to step (ii). The acid can be sulfuric acid, hydrochloric acid, citric acid, or a combination thereof. In various embodiments, the method can further comprise dewatering the tobacco material, for example using at least one of a screw press and a basket centrifuge, following steps (i), (ii) and/or step (iii).

In various embodiments of the present invention, the aqueous solution used to extract the tobacco material in step (i) can comprise a chelating agent. For example, the aqueous solution can include ethylenediaminetetraacetic acid (EDTA) and/or diethylenetriamine pentaacetic acid (DTPA). In various embodiments, the molar ratio of aqueous solution to the tobacco material in the extraction step (i) is from about 4:1 to about 16:1.

In various embodiments, the step of treating the tobacco solid material with a caustic wash is done at atmospheric pressure. In some embodiments, the caustic wash comprises at least one strong base. For example, the caustic wash can comprise sodium hydroxide. In certain embodiments, the methods described herein can further comprise mixing the tobacco solids material with a wood pulp prior to step (ii). In certain embodiments, the methods described herein can further comprise mixing the tobacco solids material with a wood pulp after step (ii).

In some embodiments, the bleaching step (iii) comprises treatment with a strong base and an oxidizing agent, and wherein the molar ratio of the amount of strong base to the amount of oxidizing agent is from about 1:1 to about 1:100, or from about 1:5 to about 1:50. In some embodiments, the bleaching step (iii) comprises treatment with one or more of peracetic acid, sodium hydroxide, and hydrogen peroxide. In various embodiments, the bleaching step (iii) further comprises treatment with one or more stabilizers in addition to an oxidizing agent. For example, the stabilizers can be selected from the group consisting of magnesium sulfate, sodium silicate, and combinations thereof. In certain embodiments, the method further includes neutralizing the bleached pulp material to a pH in the range of about 5 to about 11 prior to step (iv).

In various embodiments, the method further includes incorporating the whitened tobacco material within a smokeless tobacco product. In certain embodiments, the whitened tobacco material can be milled before incorporating the tobacco material into a tobacco product to a size in the range of about 10 mm to about 0.1 mm. In addition to the whitened tobacco material, the smokeless tobacco product can further include one or more additional components selected from the group consisting of flavorants, fillers, binders, pH adjusters, buffering agents, colorants, disintegration aids, antioxidants, humectants, and preservatives.

A smokeless tobacco product incorporating the whitened tobacco materials described herein is also provided. In some embodiments, the smokeless tobacco product can include a water-permeable pouch containing the whitened tobacco material. In various embodiments, the smokeless tobacco product can further include one or more additional components selected from the group consisting of flavorants, fillers, binders, pH adjusters, buffering agents, colorants, disintegration aids, antioxidants, humectants, and preservatives.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front perspective view illustrating a pouched product according to an embodiment; and

FIG. 2 is a flow chart illustrating the general steps for preparing a whitened tobacco material according to an embodiment.

DETAILED DESCRIPTION

Aspects of the present disclosure now will be described more fully hereinafter. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. As used in this specification and the claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Reference to “dry weight percent” or “dry weight basis” refers to weight on the basis of dry ingredients (i.e., all ingredients except water).

Certain embodiments will be described with reference to FIG. 1 of the accompanying drawings, and these described embodiments involve snus-type products having an outer pouch and containing a whitened tobacco material within the tobacco formulation. As explained in greater detail below, such embodiments are provided by way of example only, and the smokeless tobacco product can include tobacco compositions in other forms.

Referring to FIG. 1, there is shown a first embodiment of a smokeless tobacco product 10. The tobacco product 10 includes a moisture-permeable container in the form of a pouch 20, which contains a solid tobacco filler material 15 comprising a whitened tobacco material of a type described herein. The smokeless tobacco product also may optionally comprise, in certain embodiments, a plurality of microcapsules dispersed within the tobacco filler material 15, the microcapsules containing a component (e.g., a flavorant) such as described in greater detail below.

The tobacco product 10 is typically used by placing one pouch containing the tobacco formulation in the mouth of a human subject/user. During use, saliva in the mouth of the user causes some of the components of the tobacco formulation to pass through the water-permeable pouch and into the mouth of the user. The pouch preferably is not chewed or swallowed. The user is provided with tobacco flavor and satisfaction, and is not required to spit out any portion of the tobacco formulation. After about 10 minutes to about 60 minutes, typically about 15 minutes to about 45 minutes, of use/enjoyment, substantial amounts of the tobacco formulation and the contents of the optional microcapsules and have been ingested by the human subject, and the pouch may be removed from the mouth of the human subject for disposal. In certain embodiments, the pouch materials can be designed and manufactured such that under conditions of normal use, a significant amount of the tobacco formulation contents permeate through the pouch material prior to the time that the pouch undergoes loss of its physical integrity.

The present disclosure provides a whitened tobacco composition, smokeless tobacco products incorporating such whitened tobacco compositions, and methods for preparing a whitened tobacco composition and for incorporating such compositions within smokeless tobacco products. As used herein, the term “whitened” refers to a composition comprising a tobacco material that has been treated to remove some degree of color therefrom. Thus, a “whitened” tobacco material that is treated according to the methods described herein is visually lighter in hue than an untreated tobacco material. The whitened tobacco composition of the invention can be used as a component of a smokeless tobacco composition, such as loose moist snuff, loose dry snuff, chewing tobacco, pelletized tobacco pieces, extruded or formed tobacco strips, pieces, rods, or sticks, finely divided ground powders, finely divided or milled agglomerates of powdered pieces and components, flake-like pieces, molded processed tobacco pieces, pieces of tobacco-containing gum, rolls of tape-like films, readily water-dissolvable or water-dispersible films or strips, or capsule-like materials.

Tobaccos used in the tobacco compositions of the invention may vary. In certain embodiments, tobaccos that can be employed include flue-cured or Virginia (e.g., K326), burley, sun-cured (e.g., Indian Kurnool and Oriental tobaccos, including Katerini, Prelip, Komotini, Xanthi and Yambol tobaccos), Maryland, dark, dark-fired, dark air cured (e.g., Passanda, Cubano, Jatin and Bezuki tobaccos), light air cured (e.g., North Wisconsin and Galpao tobaccos), Indian air cured, Red Russian and Rustica tobaccos, as well as various other rare or specialty tobaccos and various blends of any of the foregoing tobaccos. Descriptions of various types of tobaccos, growing practices and harvesting practices are set forth in Tobacco Production, Chemistry and Technology, Davis et al. (Eds.) (1999), which is incorporated herein by reference. Various representative other types of plants from the Nicotiana species are set forth in Goodspeed, The Genus Nicotiana, (Chonica Botanica) (1954); U.S. Pat. No. 4,660,577 to Sensabaugh, Jr. et al.; U.S. Pat. No. 5,387,416 to White et al. and U.S. Pat. No. 7,025,066 to Lawson et al.; US Patent Appl. Pub. Nos. 2006/0037623 to Lawrence, Jr. and 2008/0245377 to Marshall et al.; each of which is incorporated herein by reference. Exemple Nicotiana species include N. tabacum, N. rustica, N. alata, N. arentsii, N. excelsior, N. forgetiana, N. glauca, N. glutinosa, N. gossei, N. kawakamii, N. knightiana, N. langsdorffi, N. otophora, N. setchelli, N. sylvestris, N. tomentosa, N. tomentosiformis, N. undulata, N. x sanderae, N. africana, N. amplexicaulis, N. benavidesii, N. bonariensis, N. debneyi, N. longiflora, N. maritina, N. megalosiphon, N. occidentalis, N. paniculata, N. plumbaginifolia, N. raimondii, N. rosulata, N. simulans, N. stocktonii, N. suaveolens, N. umbratica, N. velutina, N. wigandioides, N. acaulis, N. acuminata, N. attenuata, N. benthamiana, N. cavicola, N. clevelandii, N. cordifolia, N. corymbosa, N. fragrans, N. goodspeedii, N. linearis, N. miersii, N. nudicaulis, N. obtusifolia, N. occidentalis subsp. Hersperis, N. pauciflora, N. petunioides, N. quadrivalvis, N. repanda, N. rotundifolia, N. solanifolia, and N. spegazzinii.

Nicotiana species can be derived using genetic-modification or crossbreeding techniques (e.g., tobacco plants can be genetically engineered or crossbred to increase or decrease production of components, characteristics or attributes). See, for example, the types of genetic modifications of plants set forth in U.S. Pat. No. 5,539,093 to Fitzmaurice et al.; U.S. Pat. No. 5,668,295 to Wahab et al.; U.S. Pat. No. 5,705,624 to Fitzmaurice et al.; U.S. Pat. No. 5,844,119 to Weigl; U.S. Pat. No. 6,730,832 to Dominguez et al.; U.S. Pat. No. 7,173,170 to Liu et al.; U.S. Pat. No. 7,208,659 to Colliver et al. and U.S. Pat. No. 7,230,160 to Benning et al.; US Patent Appl. Pub. No. 2006/0236434 to Conkling et al.; and PCT WO 2008/103935 to Nielsen et al. See, also, the types of tobaccos that are set forth in U.S. Pat. No. 4,660,577 to Sensabaugh, Jr. et al.; U.S. Pat. No. 5,387,416 to White et al.; and U.S. Pat. No. 6,730,832 to Dominguez et al., each of which is incorporated herein by reference. Most preferably, the tobacco materials are those that have been appropriately cured and aged. Especially preferred techniques and conditions for curing flue-cured tobacco are set forth in Nestor et al., Beitrage Tabakforsch. Int., 20 (2003) 467-475 and U.S. Pat. No. 6,895,974 to Peele, which are incorporated herein by reference. Representative techniques and conditions for air curing tobacco are set forth in Roton et al., Beitrage Tabakforsch. Int., 21 (2005) 305-320 and Staaf et al., Beitrage Tabakforsch. Int., 21 (2005) 321-330, which are incorporated herein by reference. Certain types of unusual or rare tobaccos can be sun cured. Manners and methods for improving the smoking quality of Oriental tobaccos are set forth in U.S. Pat. No. 7,025,066 to Lawson et al., which is incorporated herein by reference. Representative Oriental tobaccos include katerini, prelip, komotini, xanthi and yambol tobaccos. Tobacco compositions including dark air cured tobacco are set forth in US Patent Appl. Pub. No. 2008/0245377 to Marshall et al., which is incorporated herein by reference. See also, types of tobacco as set forth, for example, in US Patent Appl. Pub. No. 2011/0247640 to Beeson et al., which is incorporated herein by reference.

The Nicotiana species can be selected for the content of various compounds that are present therein. For example, plants can be selected on the basis that those plants produce relatively high quantities of one or more of the compounds desired to be isolated therefrom. In certain embodiments, plants of the Nicotiana species (e.g., Galpao commun tobacco) are specifically grown for their abundance of leaf surface compounds. Tobacco plants can be grown in greenhouses, growth chambers, or outdoors in fields, or grown hydroponically.

Various parts or portions of the plant of the Nicotiana species can be employed. For example, virtually all of the plant (e.g., the whole plant) can be harvested, and employed as such. Alternatively, various parts or pieces of the plant can be harvested or separated for further use after harvest. For example, the flower, leaves, stem, stalk, roots, seeds, and various combinations thereof, can be isolated for further use or treatment. In some embodiments, the tobacco material subjected to the treatments set forth herein is Rustica stems in milled form.

The post-harvest processing of the plant or portion thereof can vary. After harvest, the plant, or portion thereof, can be used in a green form (e.g., the plant or portion thereof can be used without being subjected to any curing process). For example, the plant or portion thereof can be used without being subjected to significant storage, handling or processing conditions. In certain situations, it is advantageous for the plant or portion thereof be used virtually immediately after harvest. Alternatively, for example, a plant or portion thereof in green form can be refrigerated or frozen for later use, freeze dried, subjected to irradiation, yellowed, dried, cured (e.g., using air drying techniques or techniques that employ application of heat), heated or cooked (e.g., roasted, fried or boiled), or otherwise subjected to storage or treatment for later use.

The harvested plant or portion thereof can be physically processed. The plant or portion thereof can be separated into individual parts or pieces (e.g., the leaves can be removed from the stems, and/or the stems and leaves can be removed from the stalk). The harvested plant or individual parts or pieces can be further subdivided into parts or pieces (e.g., the leaves can be shredded, cut, comminuted, pulverized, milled or ground into pieces or parts that can be characterized as filler-type pieces, granules, particulates or fine powders). The plant, or parts thereof, can be subjected to external forces or pressure (e.g., by being pressed or subjected to roll treatment). When carrying out such processing conditions, the plant or portion thereof can have a moisture content that approximates its natural moisture content (e.g., its moisture content immediately upon harvest), a moisture content achieved by adding moisture to the plant or portion thereof, or a moisture content that results from the drying of the plant or portion thereof. For example, powdered, pulverized, ground or milled pieces of plants or portions thereof can have moisture contents of less than about 25 weight percent, often less than about 20 weight percent, and frequently less than about 15 weight percent.

Tobacco compositions intended to be used in a smokeless form such as that in FIG. 1 may incorporate a single type of tobacco (e.g., in a so-called “straight grade” form). For example, the tobacco within a tobacco composition may be composed solely of flue-cured tobacco (e.g., all of the tobacco may be composed, or derived from, either flue-cured tobacco lamina or a mixture of flue-cured tobacco lamina and flue-cured tobacco stem). In one embodiment, the tobacco comprises or is composed solely of sun-cured milled Rustica stems (i.e., N. rustica stems). The tobacco within a tobacco composition also may have a so-called “blended” form. For example, the tobacco within a tobacco composition of the present invention may include a mixture of parts or pieces of flue-cured, burley (e.g., Malawi burley tobacco) and Oriental tobaccos (e.g., as tobacco composed of, or derived from, tobacco lamina, or a mixture of tobacco lamina and tobacco stem).

Portions of the tobaccos within the tobacco product may have processed forms, such as processed tobacco stems (e.g., cut-rolled stems, cut-rolled-expanded stems or cut-puffed stems), or volume expanded tobacco (e.g., puffed tobacco, such as dry ice expanded tobacco (DIET)). See, for example, the tobacco expansion processes set forth in U.S. Pat. No. 4,340,073 to de la Burde et al.; U.S. Pat. No. 5,259,403 to Guy et al.; and U.S. Pat. No. 5,908,032 to Poindexter, et al.; and U.S. Pat. No. 7,556,047 to Poindexter, et al., all of which are incorporated by reference. In addition, the tobacco product optionally may incorporate tobacco that has been fermented. See, also, the types of tobacco processing techniques set forth in PCT WO 05/063060 to Atchley et al., which is incorporated herein by reference.

In certain embodiments, the starting tobacco material can include tobacco stems. As used herein, “stem” refers to the long thing part of a tobacco plant from which leaves or flowers grow, and can include the leaves, lamina, and/or flowers. In some embodiments, it can be advantageous to use stalks and/or roots of the tobacco plant. The tobacco stalks and/or roots can be separated into individual pieces (e.g., roots separated from stalks, and/or root parts separated from each other, such as big root, mid root, and small root parts) or the stalks and roots may be combined. By “stalk” is meant the stalk that is left after the leaf (including stem and lamina) has been removed. “Root” and various specific root parts useful according to the present invention may be defined and classified as described, for example, in Mauseth, Botany: An Introduction to Plant Biology: Fourth Edition, Jones and Bartlett Publishers (2009) and Glimn-Lacy et al., Botany Illustrated, Second Edition, Springer (2006), which are incorporated herein by reference. The harvested stalks and/or roots are typically cleaned, ground, and dried to produce a material that can be described as particulate (i.e., shredded, pulverized, ground, granulated, or powdered). As used herein, stalks and/or roots can also refer to stalks and/or roots that have undergone an extraction process to remove water soluble materials. The cellulosic material (i.e., pulp) remaining after stalks and/or root materials undergo an extraction process can also be useful in the present invention.

Although the tobacco material may comprise material from any part of a plant of the Nicotiana species, in certain embodiments, the majority of the material can comprise material obtained from the stems, stalks and/or roots of the plant. For example, in certain embodiments, the tobacco material comprises at least about 90%, at least about 92%, at least about 95%, or at least about 97% by dry weight of at least one of the stem material, the stalk material and the root material of a harvested plant of the Nicotiana species.

The tobacco material used in the present invention is typically provided in a shredded, ground, granulated, fine particulate, or powder form. As illustrated at operation 100 of FIG. 2, the tobacco whitening process described herein can include optionally milling a tobacco material. Most preferably, the tobacco is employed in the form of parts or pieces that have an average particle size less than that of the parts or pieces of shredded tobacco used in so-called “fine cut” tobacco products. Typically, the very finely divided tobacco particles or pieces are sized to pass through a screen of about 18 or 16 U.S. sieve size, generally are sized to pass a screen of about 20 U.S. sieve size, often are sized to pass through a screen of about 50 U.S. sieve size, frequently are sized to pass through a screen of about 60 U.S. sieve size, may even be sized to pass through a screen of 100 U.S. sieve size, and further may be sized so as to pass through a screen of 200 U.S. sieve size. It is noted that two scales commonly used to classify particle sizes are the U.S. Sieve Series and Tyler Equivalent. Sometimes these two scales are referred to as Tyler Mesh Size or Tyler Standard Sieve Series. U.S. sieve size is referred to in the present application. If desired, air classification equipment may be used to ensure that small sized tobacco particles of the desired sizes, or range of sizes, may be collected. In one embodiment, the tobacco material is in particulate form sized to pass through an 18 or 16 U.S. sieve size, but not through a 60 U.S. sieve size. If desired, differently sized pieces of granulated tobacco may be mixed together. Typically, the very finely divided tobacco particles or pieces suitable for snus products have a particle size greater than −8 U.S. sieve size, often −8 to +100 U.S. sieve size, frequently −16 to +60 U.S. sieve size. In certain embodiments, the tobacco is provided with an average particle size of about 0.2 to about 2 mm, about 0.5 to about 1.5 mm, about 0.2 to about 1.0 mm, or about 0.75 to about 1.25 mm (e.g., about 1 mm).

The manner by which the tobacco is provided in a finely divided or powder type of form may vary. Preferably, tobacco parts or pieces are comminuted, ground or pulverized into a powder type of form using equipment and techniques for grinding, milling, or the like. Most preferably, the tobacco is relatively dry in form during grinding or milling, using equipment such as hammer mills, cutter heads, air control mills, or the like. For example, tobacco parts or pieces may be ground or milled when the moisture content thereof is less than about 15 weight percent to less than about 5 weight percent. The tobacco material can be processed to provide it in the desired form before and/or after being subjected to the whitening and/or clarification processes described herein.

In some embodiments, the type of tobacco material that is treated (i.e., subjected to the processes described herein) is selected such that it is initially visually lighter in color than other tobacco materials to some degree. Accordingly, one optional step of the method described herein comprises screening various tobacco materials and selecting one or more of the tobacco materials based on their visual appearance (i.e., their “lightness,” or “whiteness”). Where conducted, this screening step can, in some embodiments, comprise a visual screening wherein certain tobacco materials (e.g., certain tobacco types) are selected that are visually lighter in hue than other tobacco materials. In some embodiments, the screening can be conducted by means of an automated operation that selects certain tobacco materials based on predetermined characteristics (e.g., having a lightness above a given threshold value). For example, optical instruments (e.g., spectrophotometer/spectroreflectometer) and/or optical sorting equipment can be used for this purpose. Such equipment is available, for example, from Autoelrepho® Products, AZ Technology, Hunter Lab, X-Rite, SpecMetrix, and others.

In various embodiments, the tobacco material can be treated to extract a soluble component of the tobacco material therefrom. As illustrated in FIG. 2, this first treatment step can comprise a solvent extraction at operation 105 comprising contacting the tobacco material with a solvent (e.g., water) for a time and at a temperature sufficient to cause the extraction of one or more components of the tobacco material into the solvent, and separating the extract from the residual tobacco solid material. “Tobacco solid material” as used herein is the solid, residual tobacco material that remains after the liquid component (i.e., tobacco extract) is removed from the material in step 105. “Tobacco extract” as used herein refers to the isolated components of a tobacco material that are extracted from solid tobacco pulp by a solvent that is brought into contact with the tobacco material in an extraction process in step 105.

Various extraction techniques of tobacco materials can be used to provide a tobacco extract and tobacco solid material. See, for example, the extraction processes described in US Pat. Appl. Pub. No. 2011/0247640 to Beeson et al., which is incorporated herein by reference. Other exemple techniques for extracting components of tobacco are described in U.S. Pat. No. 4,144,895 to Fiore; U.S. Pat. No. 4,150,677 to Osborne, Jr. et al.; U.S. Pat. No. 4,267,847 to Reid; U.S. Pat. No. 4,289,147 to Wildman et al.; U.S. Pat. No. 4,351,346 to Brummer et al.; U.S. Pat. No. 4,359,059 to Brummer et al.; U.S. Pat. No. 4,506,682 to Muller; U.S. Pat. No. 4,589,428 to Keritsis; U.S. Pat. No. 4,605,016 to Soga et al.; U.S. Pat. No. 4,716,911 to Poulose et al.; U.S. Pat. No. 4,727,889 to Niven, Jr. et al.; U.S. Pat. No. 4,887,618 to Bernasek et al.; U.S. Pat. No. 4,941,484 to Clapp et al.; U.S. Pat. No. 4,967,771 to Fagg et al.; U.S. Pat. No. 4,986,286 to Roberts et al.; U.S. Pat. No. 5,005,593 to Fagg et al.; U.S. Pat. No. 5,018,540 to Grubbs et al.; U.S. Pat. No. 5,060,669 to White et al.; U.S. Pat. No. 5,065,775 to Fagg; U.S. Pat. No. 5,074,319 to White et al.; U.S. Pat. No. 5,099,862 to White et al.; U.S. Pat. No. 5,121,757 to White et al.; U.S. Pat. No. 5,131,414 to Fagg; U.S. Pat. No. 5,131,415 to Munoz et al.; U.S. Pat. No. 5,148,819 to Fagg; U.S. Pat. No. 5,197,494 to Kramer; U.S. Pat. No. 5,230,354 to Smith et al.; U.S. Pat. No. 5,234,008 to Fagg; U.S. Pat. No. 5,243,999 to Smith; U.S. Pat. No. 5,301,694 to Raymond et al.; U.S. Pat. No. 5,318,050 to Gonzalez-Parra et al.; U.S. Pat. No. 5,343,879 to Teague; U.S. Pat. No. 5,360,022 to Newton; U.S. Pat. No. 5,435,325 to Clapp et al.; U.S. Pat. No. 5,445,169 to Brinkley et al.; U.S. Pat. No. 6,131,584 to Lauterbach; U.S. Pat. No. 6,298,859 to Kierulff et al.; U.S. Pat. No. 6,772,767 to Mua et al.; and U.S. Pat. No. 7,337,782 to Thompson, all of which are incorporated by reference herein. In certain embodiments, the solvent is added to the tobacco material and the material is soaked for a given period of time (e.g., about 1 h); the pulp is then filtered to give a tobacco solid material and the solvent and any solubles contained therein are filtered off to give a tobacco extract.

The solvent used for extraction of the tobacco material can vary. For example, in some embodiments, the solvent comprises a solvent having an aqueous character, such as distilled water and/or tap water. In some embodiments, the solvent can have one or more additives and may contain, for example, organic and/or inorganic acids, bases, or salts, pH buffers, surfactants, or combinations thereof and may comprise minor amounts of one or more organic solvents (e.g., various alcohols, polyols, and/or humectants). In one particular embodiment, the solvent comprises sodium hydroxide (NaOH) (e.g., as a 5% NaOH solution in water). In other embodiments, the solvent can comprise an organic solvent, such as an alcohol (e.g., ethanol, isopropanol, etc.), which can be used alone or in combination with an aqueous solvent. Typically, the extraction comprises adding a large excess of one or more solvents to the tobacco material so as to produce a slurry (comprising, for example, 50-90% by weight of the solvent), although the amount of solvent can vary. The solvent can be at room temperature or at an elevated temperature. For example, the solvent can be heated at a temperature of between about room temperature and about 120° C., preferably about room temperature and about 110° C. (e.g., about 100° C., about 80° C., about 60° C., about 40° C., or about 20° C.).

In some preferred embodiments, the particulate or powder tobacco material can be combined with water to form a moist aqueous material (e.g., in the form of a suspension or slurry) and the resulting material is typically heated to effectuate extraction of various compounds. The water used to form the moist material can be pure water (e.g., tap water or deionized water) or a mixture of water with suitable co-solvents such as certain alcohols. In certain embodiments, the amount of water added to form the moist material can be at least about 50 weight percent, or at least about 60 weight percent, or at least about 70 weight percent, based on the total weight of the moist material. In some cases, the amount of water can be described as at least about 80 weight percent or at least about 90 weight percent.

In certain embodiments, the tobacco material can be extracted with water and at least one chelating agent which is capable of removing transition metals from the tobacco material. Chelating agents are useful to remove certain metals from the tobacco material that could cause yellowing, and thus interfere with the whitening process. For example, the tobacco material can be extracted with an aqueous solution comprising ethylenediaminetetraacetic acid (EDTA). In some embodiments, the chelating agent can comprise diethylenetriamine pentaacetic acid (DTPA). In various embodiments, the chelating agent(s) can be present in an amount of about 0.01 to about 1.0 dry weight percent, about 0.05 to about 0.5 dry weight percent, or about 0.1 to about 0.2 dry weight percent, based on the total dry weight of the tobacco material.

The amount of time for which the tobacco material remains in contact with the solvent can vary. For example, in some embodiments, the tobacco material is in contact with the solvent for about thirty minutes to about six hours (e.g., about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, or about 6 hours), although shorter and longer time periods can be used. The amount of time can depend, for example, on the temperature of the solvent. For example, less time may be required to extract the tobacco material using solvent at a higher temperature than that required to extract the tobacco material with room temperature or cold solvent. The extraction process provides a tobacco solid material and a tobacco extract.

The number of extraction steps can vary. For example, in certain embodiments, the tobacco pulp is extracted one or more times, two or more times, three or more times, four or more times, or five or more times. The solvent used for each extraction can vary. For example, in one particular embodiment, one or more extractions are conducted using hot water; and in a final extraction, the extraction is conducted using a basic solution (e.g., a 5% NaOH solution). After each extraction step, the tobacco solid material is filtered and the solvent and solubles are removed from the tobacco solid material. In certain embodiments, the extracts obtained from each extraction can be combined and clarified, as described in U.S. Pat. No. 9,420,825 to Beeson et al., which is herein incorporated by reference in its entirety. In other embodiments, some extracts are discarded, such as extracts from later stages. In such embodiments, for example, it may be desirable in some embodiments to use only the tobacco extract obtained from a first extraction of a tobacco material or to combine tobacco extracts obtained from a first and second extraction of a tobacco material.

Following the extraction process, the tobacco pulp is generally isolated from the tobacco extract, for example, by filtration or centrifugation, although these methods are not intended to be limiting. Alternatively, in some embodiments, the tobacco pulp can be isolated from the extract by means of distillation (e.g., steam distillation) of the tobacco mixture (e.g., the tobacco slurry). The process of filtration can comprise passing the liquid through one or more filter screens to remove selected sizes of particulate matter. Screens may be, for example, stationary, vibrating, rotary, or any combination thereof. Filters may be, for example, press filters or pressure filters. In some embodiments, the filtration method used can involve microfiltration, ultrafiltration, and/or nanofiltration. A filter aid can be employed to provide effective filtration and can comprise any material typically used for this purpose. For example, some common filter aids include cellulose fibers, perlite, bentonite, diatomaceous earth, and other silaceous materials. To remove solid components, alternative methods can also be used, for example, centrifugation or settling/sedimentation of the components and siphoning off of the liquid. See, for example, the processes and products described in U.S. Pat. App. Pub. Nos. 2012/0152265 to Dube et al. and 2012/0192880 to Dube et al., herein incorporated by reference in their entireties. The extracted solid components can be used as the starting tobacco material in various embodiments of the whitening process described herein.

In various embodiments, the tobacco material can be hydrolyzed with at least one acid, as illustrated at operation 110 of FIG. 2, for example. Steam- or water-based pre-hydrolysis of the tobacco material prior to pulping, for example, can reduce the amount of chemicals necessary in a bleaching operation. Any form of hydrolysis known in the art can be used. In certain embodiments, a salt of a weak acid or a weak base (or both) can be dissolved in water in a hydrolysis process. In various embodiments, tobacco materials can undergo enzymatic hydrolysis. In certain embodiments, the tobacco material can be hydrolyzed with sulfuric acid, hydrochloric acid, or any other mineral or organic acid.

The tobacco material will undergo a pulping process, as illustrated at operation 115 in FIG. 2, for example. Pulps can be produced from raw materials either mechanically or chemically. For example, refiner mechanical pulping techniques can be used to produce tobacco pulp. In a mechanical pulping process, raw tobacco materials can be chipped, and then fed between refiners where the chips are made into fibers between revolving metal disks, for example. See, e.g., the mechanical pulping equipment and processes disclosed in U.S. Pat. No. 4,421,595 to Huusari and U.S. Pat. No. 7,237,733 to Vikman, WO 2010/023363, CA 1074606, and CN 201268810, all of which are herein incorporated by reference in their entireties.

As discussed above, in some embodiments, raw tobacco material can be pretreated (i.e., extracted) with water for several hours before undergoing the pulping process. The weight ratio of water to tobacco material can be approximately 10:1 to about 4:1. Pretreating the tobacco material (e.g., stalk and/or root materials) can soften the starting tobacco material and remove water soluble extracts. The pretreated mixture can then be drained to about a 20% consistency. As used herein, the term “consistency” is defined as the percentage of solids in a mixture. This pretreated tobacco material can then be refined at atmospheric pressure with a plurality of passes through a machine that can chip the stalk. See, for example, the machines discussed in U.S. Pat. No. 3,661,192 to Nicholson et al.; U.S. Pat. No. 3,861,602 to Smith et al.; U.S. Pat. No. 4,135,563 to Maucher; and U.S. Pat. No. 5,005,620 to Morey, each of which is incorporated by reference herein.

In some embodiments, a chemical pulping process can be used to pulp and delignify the tobacco biomass at operation 115. A chemical pulping process separates lignin from cellulose fibers by dissolving lignin in a cooking liquor such that the lignin, which binds the cellulose fibers together, can be washed away from the cellulose fibers without seriously degrading the cellulose fibers. There are three main chemical pulping processes known in the art. Soda pulping involves cooking raw material chips in a sodium hydroxide cooking liquor. The kraft process evolved from soda pulping and involves cooking raw material chips in a solution of sodium hydroxide and sodium sulfide. The acidic sulfite process involves using sulfurous acid and bisulfate ion in the cook. The kraft process is the most commonly used method for chemical wood pulping; however, the soda process can also be used to produce some hardwood pulps. Any chemical pulping process, including, but not limited to the three examples listed above, can be used to produce a tobacco pulp from raw tobacco materials.

A cooking liquor can comprise a strong base. As used herein, a strong base refers to a basic chemical compound (or combination of such compounds) that is able to deprotonate very weak acids in an acid-base reaction. For example, strong bases that can be useful in the present invention include, but are not limited to one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium hydroxide, ammonium bicarbonate, and ammonium carbonate. In some embodiments, the weight of the strong base can be greater than about 5%, greater than about 25%, or greater than about 40% of the weight of the tobacco input. In certain embodiments, the weight of the strong base can be less than about 60% or less than about 50% of the weight of the tobacco input. In still further embodiments, the weight of the strong base can be from about 5% to about 50%, or from about 30% to about 40% of the weight of the tobacco input. Various other chemicals and weight ratios thereof can also be employed to chemically pulp the tobacco input in other embodiments.

In addition to combining a tobacco input with a strong base, chemically pulping a tobacco input can include heating the tobacco input and the strong base. Heating the tobacco input and the strong base can be conducted to increase the efficacy of the chemical pulping. In this regard, an increase in either cooking temperature or time will result in an increased reaction rate (rate of lignin removal).

In some embodiments, the method of producing a tobacco-derived pulp can include one or more additional operations. See, e.g., U.S. Patent Appl. Pub. No. 2013/0276801 to Byrd Jr. et al., herein incorporated by reference in its entirety. For example, the tobacco input can undergo further processing steps prior to pulping and/or the delignification method can include additional treatment steps (e.g., drying the tobacco input, or depithing the tobacco input). In some embodiments, these additional steps can be conducted to remove pith (which comprises lignin) from the tobacco input and/or tobacco pulp manually, and thus reduce the amount of chemicals necessary to delignify the tobacco input during a chemical pulping process, for example. Mixing water with the tobacco pulp to form a slurry and filtering the slurry can be conducted, for example, to remove certain materials, such as pith, parenchyma, and tissue from the tobacco pulp. Anthraquinone can be employed in a chemical pulping method in an attempt to provide a higher yield by protecting carbohydrates from the strong base during delignification, for example. Other processing steps known in the pulping and delignification field can be employed in forming tobacco pulp from the raw tobacco input.

In various embodiments, a wood pulp is added to the solid tobacco materials and/or the tobacco pulp during the overall bleaching processes described herein. It is noted that wood pulp can be introduced into the bleaching process at any of the steps described herein. For example, in certain embodiments, the methods described herein can further comprise mixing the tobacco solids material with a wood material prior to pulping such that the wood material is also pulped. In certain embodiments, the methods described herein can further comprise mixing the tobacco pulp with a wood pulp after the pulping process. In some embodiments, the wood pulp is a bleached pulp material and can be added after the solid tobacco materials have been pulped and bleached. If unbleached wood pulp is used, an additional caustic extraction step may be required, or the wood pulp can need to be added to the tobacco pulp before the step of bleaching.

In various embodiments, the wood pulp can be market available wood pulp. In certain embodiments, the wood pulp can be a bleached hardwood pulp. The wood pulp added to the processes described herein can be added in an amount of about 1 to about 20 wt. %, or about 5 to about 15 wt. %, based on the total weight of the pulp used (i.e., the total weight of tobacco pulp and wood pulp used). In some embodiments, the wood pulp can be added in an amount of at least about 1 wt. %, at least about 5 wt. %, or at least about 10 wt. %, based on the total weight of the pulp used. In certain embodiments, the wood pulp can be added in an amount of no more than about 5 wt. %, no more than about 10 wt. %, no more than about 15 wt. %, or no more than about 20 wt. %, based on the total weight of the pulp used.

Tobacco pulp that has been provided and isolated following the extraction and pulping steps can be whitened in certain embodiments according to any means known in the art, as shown in step 120 of FIG. 2. It is noted that in certain embodiments, a combination of tobacco pulp and wood pulp may undergo a whitening step or any other process step described herein; however, for convenience, the following description refers only to tobacco pulp. For example, whitening methods using various bleaching or oxidizing agents and oxidation catalysts can be used. Example oxidizing agents include peroxides (e.g., hydrogen peroxide), chlorite salts, chlorate salts, perchlorate salts, hypochlorite salts, ozone, ammonia, and combinations thereof. Example oxidation catalysts are titanium dioxide, manganese dioxide, and combinations thereof. Processes for treating tobacco with bleaching agents are discussed, for example, in U.S. Pat. No. 787,611 to Daniels, Jr.; U.S. Pat. No. 1,086,306 to Oelenheinz; U.S. Pat. No. 1,437,095 to Delling; U.S. Pat. No. 1,757,477 to Rosenhoch; U.S. Pat. No. 2,122,421 to Hawkinson; U.S. Pat. No. 2,148,147 to Baier; U.S. Pat. No. 2,170,107 to Baier; U.S. Pat. No. 2,274,649 to Baier; U.S. Pat. No. 2,770,239 to Prats et al.; U.S. Pat. No. 3,612,065 to Rosen; U.S. Pat. No. 3,851,653 to Rosen; U.S. Pat. No. 3,889,689 to Rosen; U.S. Pat. No. 3,943,945 to Rosen; U.S. Pat. No. 4,143,666 to Rainer; U.S. Pat. No. 4,194,514 to Campbell; U.S. Pat. Nos. 4,366,823, 4,366,824, and 4,388,933 to Rainer et al.; U.S. Pat. No. 4,641,667 to Schmekel et al.; and U.S. Pat. No. 5,713,376 to Berger; and PCT WO 96/31255 to Giolvas, all of which are incorporated herein by reference. Other whitening methods using reagents such as ozone and potassium permanganate can also be used. See, for example, U.S. Pat. No. 3,943,940 to Minami, which is incorporated herein by reference.

In certain embodiments of the present invention, tobacco pulp is whitened using a caustic reagent and/or an oxidizing agent. In some embodiments, the tobacco pulp is whitened using both a caustic reagent and an oxidizing agent. In such embodiments, the caustic reagent and oxidizing agent can be provided separately or can be combined.

The caustic reagent can vary and can be, for example, any strong base, including but not limited to, an alkaline metal hydroxide, alkaline earth metal hydroxide, or mixture thereof. In certain example embodiments, the caustic reagent is sodium hydroxide or potassium hydroxide. Alternative reagents that can be used include, but are not limited to, ammonium hydroxide, sodium carbonate, potassium carbonate, ammonia gas, and mixtures thereof. The caustic reagent is generally provided in solution form (e.g., in aqueous solution) and the concentration of the caustic reagent in the solution can vary. Also, the amount of caustic reagent used in the methods of the present invention can vary. For example, in certain embodiments, the caustic reagent is provided in an amount of between about 1% and about 50% dry weight basis (e.g., between about 1% and about 40% or between about 1% and about 30%) by weight of the (dry) tobacco pulp. For example, the caustic reagent can be provided in an amount of about 2%, about 5%, about 7%, about 10%, or about 25% by weight of the (dry) tobacco pulp. It is noted that the quantity of caustic reagent required may, in certain embodiments, vary as a result of the strength of the caustic reagent. For example, more caustic reagent may, in some embodiments, be required where the caustic reagent is a weaker base, whereas less caustic reagent may, in some embodiments, be required where the caustic reagent is a strong base.

The oxidizing agent (i.e., oxidant or oxidizer) can be any substance that readily transfers oxygen atoms and/or gains electrons in a reduction/oxidation (redox) chemical reaction. Peroxides (e.g., hydrogen peroxide, peracetic acid) are preferred oxidizing agents; however, any oxidizing reagent, including, but not limited to; other oxides (including nitrous oxide, silver oxide, chromium trioxide, chromate, dichromate, pyridinium chlorochromate; and osmium tetroxide); oxygen (O₂); ozone (O₃); fluorine (F₂); chlorine (Cl₂); and other halogens; hypochlorite, chlorite, chlorate, perchlorite, and other halogen analogues thereof; nitric acid; nitrate compounds; sulfuric acid; persulfuric acids; hydroxyl radicals; manganate and permanganate compounds (e.g., potassium permanganate); sodium perborate; 2,2′-diphyridyldisulfide; and combinations thereof can be used according to the invention. In certain preferred embodiments, the oxidizing reagent used according to the invention is chlorine-free. In certain embodiments, the oxidizing reagent is provided in aqueous solution form. The amount of oxidizing agent used in the methods of the present invention can vary. For example, in certain embodiments, the oxidizing agent is provided in a weight amount of about one to fifty times the weight of the (dry) tobacco pulp. For example, in some embodiments, the oxidizing agent is provided in a weight amount about equal to the weight of the (dry) tobacco pulp, about 1.3 times the weight of the (dry) tobacco pulp, about 1.5 times the weight of the (dry) tobacco pulp, about 2 times the weight of the (dry) tobacco pulp, or about 5 times the weight of the (dry) tobacco pulp.

In various embodiments, the bleaching process can further include treatment with one or more stabilizers in addition to an oxidizing agent. For example, the stabilizer can be selected from the group consisting of magnesium sulfate, sodium silicate, and combinations thereof. In various embodiments, the stabilizer(s) can be present in an amount of about 0.01 to about 3.0 dry weight percent, about 0.1 to about 2.5 dry weight percent, or about 0.5 to about 2.0 dry weight percent, based on the total dry weight of the tobacco material pulp.

According to the invention, the tobacco pulp is brought into contact with the caustic reagent and/or oxidizing agent for a period of time. The tobacco material can be brought into contact with the caustic reagent and oxidizing reagent simultaneously, or can be brought into contact with the caustic reagent and oxidizing reagent separately. In one embodiment, the oxidizing reagent is added to the tobacco material and then the caustic reagent is added to the tobacco material such that, after addition, both reagents are in contact with the tobacco material simultaneously. In another embodiment, the caustic reagent is added to the tobacco material and then the oxidizing reagent is added to the tobacco material such that, after addition, both reagents are in contact with the tobacco material simultaneously.

The molar ratio of the caustic reagent to oxidizing agent can vary. In certain embodiments where the caustic reagent is NaOH and the oxidizing agent is hydrogen peroxide, the molar ratio of NaOH to hydrogen peroxide is from about 1:1 to about 1:100, preferably from about 1:5 to about 1:50, and more preferably from about 1:10 to about 1:25. In one particular embodiment, the molar ratio of NaOH to hydrogen peroxide is between about 1:20 and about 1:25. These ratios are not limited to ratios of NaOH and hydrogen peroxide and could also be applicable to other caustic reagent and oxidizing agent combinations.

The time for which the tobacco material is contacted with the caustic reagent and/or oxidizing agent can vary. For example, in certain embodiments, the time for which the tobacco material is contacted with the caustic reagent and/or oxidizing agent is that amount of time sufficient to provide a tobacco pulp material with a lightened color as compared to the untreated tobacco material. In certain embodiments, the tobacco material is contacted with the caustic reagent and/or oxidizing agent overnight. Normally, the time period is a period of at least about 10 minutes, typically at least about 20 minutes, more often at least about 30 minutes. In certain embodiments, the time period is a period of no more than about 10 hours, no more than about 8 hours, no more than about 6 hours, no more than about 4 hours, no more than about 2 hours, or no more than about 1 hour.

In certain embodiments, the tobacco material can be heated during treatment with the caustic reagent and/or oxidizing agent. Generally, heating the tobacco material accelerates the whitening process. Where the tobacco material is heated during treatment, sufficient color lightening is typically achieved in less time than in embodiments wherein the tobacco material is unheated during treatment. The temperature and time of the heat treatment process will vary, and generally, the length of the heat treatment will decrease as the temperature of the heat treatment increases. In certain embodiments, the mixture of tobacco material, caustic reagent, and/or oxidizing agent can be heated at a temperature of between room temperature and about 100° C. (e.g., about 90° C. or about 80° C.). Preferably, the mixture is heated between room temperature and about 75° C. The heating, where applicable, can be accomplished using any heating method or apparatus known in the art. The heating can be carried out in an enclosed vessel (e.g., one providing for a controlled atmospheric environment, controlled atmospheric components, and a controlled atmospheric pressure), or in a vessel that is essentially open to ambient air. The temperature can be controlled by using a jacketed vessel, direct steam injection into the tobacco, bubbling hot air through the tobacco, and the like. In certain embodiments, the heating is performed in a vessel also capable of providing mixing of the composition, such as by stirring or agitation. Example mixing vessels include mixers available from Scott Equipment Company, Littleford Day, Inc., Lodige Process Technology, and the Breddo Likwifier Division of American Ingredients Company. Examples of vessels which provide a pressure controlled environment include high pressure autoclaves available from Berghof/America Inc. of Concord, California, and high pressure reactors available from The Parr Instrument Co. (e.g., Parr Reactor Model Nos. 4522 and 4552 described in U.S. Pat. No. 4,882,128 to Hukvari et al.). The pressure within the mixing vessel during the process can be atmospheric pressure or elevated pressure (e.g., about 10 psig to about 1,000 psig).

In other embodiments, the heating process is conducted in a microwave oven, a convection oven, or by infrared heating. Atmospheric air, or ambient atmosphere, is the preferred atmosphere for carrying out the optional heating step of the present invention. However, heating can also take place under a controlled atmosphere, such as a generally inert atmosphere. Gases such as nitrogen, argon and carbon dioxide can be used. Alternatively, a hydrocarbon gas (e.g., methane, ethane or butane) or a fluorocarbon gas also can provide at least a portion of a controlled atmosphere in certain embodiments, depending on the choice of treatment conditions and desired reaction products.

In certain embodiments, before drying the bleached tobacco pulp, the bleached tobacco pulp can be treated with an acid to neutralize the tobacco pulp after the bleaching process to a pH in the range of about 5 to about 11 (as illustrated at operation 125 of FIG. 2, for example), such as about 6 to about 10. The bleached tobacco pulp can be treated with sulfuric acid, hydrochloric acid, citric acid, or any combination thereof. Other acids known in the art can also be used to neutralize the bleached tobacco pulp. Following treatment with an acid, the pH of the bleached tobacco pulp can be approximately 7.

Following treatment of the tobacco pulp with the caustic reagent and/or oxidizing reagent, the treated tobacco pulp is generally filtered (i.e., isolated from the caustic reagent and/or oxidizing reagent) and dried (as illustrated at operation 130 of FIG. 2, for example) to give a whitened tobacco pulp material. In certain embodiments, the tobacco pulp can be dried to a moisture level of about 1-30%, about 5-20%, or about 10-15% moisture on a wet basis.

After drying, the whitened tobacco material can optionally be milled a size in the range of approximately about 5 mm to about 0.1 mm, or about 1 mm to about 0.1 mm. In certain embodiments, the whitened tobacco material can be milled to a size of less than about 10 mm, less than about 5 mm, less than about 2 mm, or less than about 1 mm.

After drying, the whitened tobacco material can have an ISO brightness of at least about 50%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, or at least about 80%. In some embodiments, the whitened tobacco material described herein can have an ISO brightness in the range of about 50% to about 90%, about 55% to about 75%, or about 60% to about 70%. ISO brightness can be measured according to ISO 3688:1999 or ISO 2470-1:2016.

In some embodiments, the whitened tobacco pulp thus produced can be characterized as lightened in color (e.g., “whitened”) in comparison to the untreated tobacco pulp. Visual and/or instrumental assessments such as those previously described can be used to verify and, if desired, quantify the degree of lightening achieved by way of the presently described method of the invention. Assessment of the whiteness of a material generally requires comparison with another material. The extent of lightening can be quantified, for example, by spectroscopic comparison with an untreated tobacco sample (e.g., untreated tobacco pulp). White colors are often defined with reference to the International Commission on Illumination's (CIE's) chromaticity diagram. The whitened tobacco pulp can, in certain embodiments, be characterized as closer on the chromaticity diagram to pure white than untreated tobacco pulp.

The tobacco materials discussed in the present invention can be treated and/or processed in other ways before, after, or during the process steps described above. For example, if desired, the tobacco materials can be irradiated, pasteurized, or otherwise subjected to controlled heat treatment. Such treatment processes are detailed, for example, in US Pat. Pub. No. 2009/0025738 to Mua et al., which is incorporated herein by reference. In certain embodiments, tobacco materials can be treated with water and an additive capable of inhibiting reaction of asparagine to form acrylamide upon heating of the tobacco material (e.g., an additive selected from the group consisting of lysine, glycine, histidine, alanine, methionine, glutamic acid, aspartic acid, proline, phenylalanine, valine, arginine, compositions incorporating di- and trivalent cations, asparaginase, certain non-reducing saccharides, certain reducing agents, phenolic compounds, certain compounds having at least one free thiol group or functionality, oxidizing agents, oxidation catalysts, natural plant extracts (e.g., rosemary extract), and combinations thereof), and combinations thereof. See, for example, the types of treatment processes described in US Pat. Pub. Nos. 2010/0300463 and 2011/0048434 to Chen et al., and US Pat. 8,991,403 to Chen et al., which are all incorporated herein by reference. In certain embodiments, this type of treatment is useful where the original tobacco material is subjected to heat in the extraction and/or distillation process previously described.

The whitened tobacco material can be incorporated within a smokeless tobacco product according to the present invention. Depending on the type of tobacco product being processed, the tobacco product can include one or more additional components in addition to the whitened tobacco material as described above. For example, the whitened tobacco material can be processed, blended, formulated, combined and/or mixed with other materials or ingredients, such as other tobacco materials or flavorants, fillers, binders, pH adjusters, buffering agents, salts, sweeteners, colorants, oral care additives, disintegration aids, antioxidants, humectants, and preservatives. See, for example, those representative components, combination of components, relative amounts of those components and ingredients relative to tobacco, and manners and methods for employing those components, set forth in US Pat. Pub. Nos. 2011/0315154 to Mua et al.; 2007/0062549 to Holton, Jr. et al.; 2012/0067361 to Bjorkholm et al.; 2017/0020183 to Bjorkholm; and 2017/0112183 to Bjorkholm; and U.S. Pat. No. 7,861,728 to Holton, Jr. et al., each of which is incorporated herein by reference.

The relative amount of whitened tobacco material within the smokeless tobacco product may vary. Preferably, the amount of whitened tobacco material within the smokeless tobacco product is at least about 10%, at least about 25%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% on a dry weight basis of the formulation. A typical range of tobacco material within the formulation is about 10 to about 99%, more often about 50 to about 99% by weight on a dry basis.

The whitened tobacco material used for the manufacture of the smokeless tobacco products of the invention preferably is provided in a ground, granulated, fine particulate, or powdered form. Although not strictly necessary, the whitened tobacco material may be subjected to processing steps that provide a further grinding for further particle size reduction. The whitening processes of the present invention generally provide a whitened tobacco material with a decreased amount of high molecular weight compounds, leading to more interstitial room and thus higher possible water content in smokeless tobacco materials produced therefrom than those from unwhitened tobacco materials. In certain embodiments, the smokeless tobacco products produced according to the invention provide for faster nicotine release than products produced from unwhitened tobacco materials.

Example flavorants that can be used are components, or suitable combinations of those components, that act to alter the bitterness, sweetness, sourness, or saltiness of the smokeless tobacco product, enhance the perceived dryness or moistness of the formulation, or the degree of tobacco taste exhibited by the formulation. Flavorants may be natural or synthetic, and the character of the flavors imparted thereby may be described, without limitation, as fresh, sweet, herbal, confectionary, floral, fruity, or spicy. Specific types of flavors include, but are not limited to, vanilla, coffee, chocolate/cocoa, cream, mint, spearmint, menthol, peppermint, wintergreen, eucalyptus, lavender, cardamon, nutmeg, cinnamon, clove, cascarilla, sandalwood, honey, jasmine, ginger, anise, sage, licorice, lemon, orange, apple, peach, lime, cherry, strawberry, and any combinations thereof. See also, Leffingwell et al., Tobacco Flavoring for Smoking Products, R. J. Reynolds Tobacco Company (1972), which is incorporated herein by reference. Flavorings also may include components that are considered moistening, cooling or smoothening agents, such as eucalyptus. These flavors may be provided neat (i.e., alone) or in a composite (e.g., spearmint and menthol, or orange and cinnamon). Representative types of components also are set forth in U.S. Pat. No. 5,387,416 to White et al.; US Pat. App. Pub. No. 2005/0244521 to Strickland et al.; and PCT Application Pub. No. WO 05/041699 to Quinter et al., each of which is incorporated herein by reference. Types of flavorants include salts (e.g., sodium chloride, potassium chloride, sodium citrate, potassium citrate, sodium acetate, potassium acetate, and the like), natural sweeteners (e.g., fructose, sucrose, glucose, maltose, mannose, galactose, lactose, and the like), artificial sweeteners (e.g., sucralose, saccharin, aspartame, acesulfame K, neotame, and the like); and mixtures thereof. The amount of flavorants utilized in the tobacco composition can vary, but is typically up to about 10 dry weight percent, and certain embodiments are characterized by a flavorant content of at least about 1 dry weight percent, such as about 1 to about 10 dry weight percent. Combinations of flavorants are often used, such as about 0.1 to about 2 dry weight percent of an artificial sweetener, about 0.5 to about 8 dry weight percent of a salt such as sodium chloride and about 1 to about 5 dry weight percent of an additional flavoring.

Example filler materials include vegetable fiber materials such as sugar beet fiber materials (e.g., FIBREX® brand filler available from International Fiber Corporation), oats or other cereal grain (including processed or puffed grains), bran fibers, starch, or other modified or natural cellulosic materials such as microcrystalline cellulose. Additional specific examples include corn starch, maltodextrin, dextrose, calcium carbonate, calcium phosphate, lactose, manitol, xylitol, and sorbitol. The amount of filler, where utilized in the tobacco composition, can vary, but is typically up to about 20 dry weight percent, and certain embodiments are characterized by a filler content of up to about 10 dry weight percent, up to about 5 dry weight percent or up to about 1 dry weight percent. Combinations of fillers can also be used.

Typical binders can be organic or inorganic, or a combination thereof. Representative binders include povidone, sodium carboxymethylcellulose and other modified cellulosic materials, sodium alginate, xanthan gum, starch-based binders, gum arabic, pectin, carrageenan, pullulan, zein, and the like. The amount of binder utilized in the tobacco composition can vary, but is typically up to about 30 dry weight percent, and certain embodiments are characterized by a binder content of at least about 5 dry weight percent, such as about 5 to about 30 dry weight percent.

Preferred pH adjusters or buffering agents provide and/or buffer within a pH range of about 6 to about 10, and example agents include metal hydroxides, metal carbonates, metal bicarbonates, and mixtures thereof. Specific example materials include citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate, sodium carbonate, and sodium bicarbonate. The amount of pH adjuster or buffering material utilized in the tobacco composition can vary, but is typically up to about 5 dry weight percent, and certain embodiments can be characterized by a pH adjuster/buffer content of less than about 0.5 dry weight percent, such as about 0.05 to about 0.2 dry weight percent. Particularly in embodiments comprising an extract clarified by distillation, the pH may be lowered by the addition of one or more pH adjusters (e.g., citric acid).

A colorant may be employed in amounts sufficient to provide the desired physical attributes to the tobacco formulation. Example colorants include various dyes and pigments, such as caramel coloring and titanium dioxide. The amount of colorant utilized in the tobacco composition can vary, but is typically up to about 3 dry weight percent, and certain embodiments are characterized by a colorant content of at least about 0.1 dry weight percent, such as about 0.5 to about 3 dry weight percent.

Example humectants include glycerin and propylene glycol. The amount of humectant utilized in the tobacco composition can vary, but is typically up to about 5 dry weight percent, and certain embodiments can be characterized by a humectant content of at least about 1 dry weight percent, such as about 2 to about 5 dry weight percent.

Other ingredients such as preservatives (e.g., potassium sorbate), disintegration aids (e.g., microcrystalline cellulose, croscarmellose sodium, crospovidone, sodium starch glycolate, pregelatinized corn starch, and the like), and/or antioxidants can also be used. Typically, such ingredients, where used, are used in amounts of up to about 10 dry weight percent and usually at least about 0.1 dry weight percent, such as about 0.5 to about 10 dry weight percent. A disintegration aid is generally employed in an amount sufficient to provide control of desired physical attributes of the tobacco formulation such as, for example, by providing loss of physical integrity and dispersion of the various component materials upon contact of the formulation with water (e.g., by undergoing swelling upon contact with water).

As noted, in some embodiments, any of the components described above can be added in an encapsulated form (e.g., in the form of microcapsules), the encapsulated form a wall or barrier structure defining an inner region and isolating the inner region permanently or temporarily from the tobacco composition. The inner region includes a payload of an additive either adapted for enhancing one or more sensory characteristics of the smokeless tobacco product, such as taste, mouthfeel, moistness, coolness/heat, and/or fragrance, or adapted for adding an additional functional quality to the smokeless tobacco product, such as addition of an antioxidant or immune system enhancing function. See, for example, the subject matter of US Pat. Appl. Pub. No. 2009/0025738 to Mua et al., which is incorporated herein by reference.

Representative tobacco formulations may incorporate about 80% to about 95% percent whitened tobacco material, about 0.1% to about 5% artificial sweetener, about 0.5% to about 2% salt, about 1% to about 5% flavoring, about 1% to about 5% humectants (e.g., propylene glycol), and up to about 10% pH adjuster or buffering agent (e.g., sodium bicarbonate or citric acid), based on the total dry weight of the tobacco formulation. The particular percentages and choice of ingredients will vary depending upon the desired flavor, texture, and other characteristics.

The components of the tobacco composition can be brought together in admixture using any mixing technique or equipment known in the art. The optional components noted above, which may be in liquid or dry solid form, can be admixed with the whitened tobacco material in a pretreatment step prior to mixture with any remaining components of the composition or simply mixed with the whitened tobacco material together with all other liquid or dry ingredients. Any mixing method that brings the tobacco composition ingredients into intimate contact can be used. A mixing apparatus featuring an impeller or other structure capable of agitation is typically used. Example mixing equipment includes casing drums, conditioning cylinders or drums, liquid spray apparatus, conical-type blenders, ribbon blenders, mixers available as FKM130, FKM600, FKM1200, FKM2000 and FKM3000 from Littleford Day, Inc., Plough Share types of mixer cylinders, and the like. As such, the overall mixture of various components with the whitened tobacco material may be relatively uniform in nature. See also, for example, the types of methodologies set forth in U.S. Pat. No. 4,148,325 to Solomon et al.; U.S. Pat. No. 6,510,855 to Korte et al.; and U.S. Pat. No. 6,834,654 to Williams, each of which is incorporated herein by reference. Manners and methods for formulating snus-type tobacco formulations will be apparent to those skilled in the art of snus tobacco product production.

The moisture content of the smokeless tobacco product prior to use by a consumer of the formulation may vary. Typically, the moisture content of the product, as present within the pouch prior to insertion into the mouth of the user, is less than about 55 weight percent, generally is less than about 50 weight percent, and often is less than about 45 weight percent. For certain tobacco products, such as those incorporating snus-types of tobacco compositions, the moisture content may exceed 20 weight percent, and often may exceed 30 weight percent. For example, a representative snus-type product may possess a tobacco composition exhibiting a moisture content of about 20 weight percent to about 50 weight percent, preferably about 20 weight percent to about 40 weight percent.

The manner by which the moisture content of the formulation is controlled may vary. For example, the formulation may be subjected to thermal or convection heating. As a specific example, the formulation may be oven-dried, in warmed air at temperatures of about 40° C. to about 95° C., with a preferred temperature range of about 60° C. to about 80° C. for a length of time appropriate to attain the desired moisture content. Alternatively, tobacco formulations may be moistened using casing drums, conditioning cylinders or drums, liquid spray apparatus, ribbon blenders, or mixers. Most preferably, moist tobacco formulations, such as the types of tobacco formulations employed within snus types of products, are subjected to pasteurization or fermentation. Techniques for pasteurizing/heat treating and/or fermenting snus types of tobacco products will be apparent to those skilled in the art of snus product design and manufacture.

The acidity or alkalinity of the tobacco formulation, which is often characterized in terms of pH, can vary. Typically, the pH of that formulation is at least about 6.5, and preferably at least about 7.5. In some embodiments, the pH of that formulation will not exceed about 11, or will not exceed about 9, and often will not exceed about 8.5. A representative tobacco formulation exhibits a pH of about 6.8 to about 8.2 (e.g., about 7.8). A representative technique for determining the pH of a tobacco formulation involves dispersing 5 g of that formulation in 100 ml of high performance liquid chromatography water, and measuring the pH of the resulting suspension/solution (e.g., with a pH meter).

In certain embodiments, the whitened tobacco material and any other components noted above are combined within a moisture-permeable packet or pouch that acts as a container for use of the tobacco. The composition/construction of such packets or pouches, such as the container pouch 20 in the embodiment illustrated in FIG. 1, may be varied. Suitable packets, pouches or containers of the type used for the manufacture of smokeless tobacco products are available under the tradenames CatchDry, Ettan, General, Granit, Goteborgs Rape, Grovsnus White, Metropol Kaktus, Mocca Anis, Mocca Mint, Mocca Wintergreen, Kicks, Probe, Prince, Skruf, Epok, and TreAnkrare. The tobacco formulation may be contained in pouches and packaged, in a manner and using the types of components used for the manufacture of conventional snus types of products. The pouch provides a liquid-permeable container of a type that may be considered to be similar in character to the mesh-like type of material that is used for the construction of a tea bag. Components of the loosely arranged, granular tobacco formulation readily diffuse through the pouch and into the mouth of the user.

Descriptions of various components of snus types of products and components thereof also are set forth in US Pat. App. Pub. No. 2004/0118422 to Lundin et al., which is incorporated herein by reference. See, also, for example, U.S. Pat. No. 4,607,479 to Linden; U.S. Pat. No. 4,631,899 to Nielsen; U.S. Pat. No. 5,346,734 to Wydick et al.; and U.S. Pat. No. 6,162,516 to Derr, and US Pat. Pub. No. 2005/0061339 to Hansson et al.; each of which is incorporated herein by reference. See, also, the types of pouches set forth in U.S. Pat. No. 5,167,244 to Kjerstad, which is incorporated herein by reference. Snus types of products can be manufactured using equipment such as that available as SB 51-1/T, SBL 50 and SB 53-2/T from Merz Verpackungmaschinen GmBH. Snus pouches can be provided as individual pouches, or a plurality of pouches (e.g., 2, 4, 5, 10, 12, 15, 20, 25 or 30 pouches) can connected or linked together (e.g., in an end-to-end manner) such that a single pouch or individual portion can be readily removed for use from a one-piece strand or matrix of pouches.

A pouch may, for example, be manufactured from materials, and in such a manner, such that during use by the user, the pouch undergoes a controlled dispersion or dissolution. Such pouch materials may have the form of a mesh, screen, perforated paper, permeable fabric, or the like. For example, pouch material manufactured from a mesh-like form of rice paper, or perforated rice paper, may dissolve in the mouth of the user. As a result, the pouch and tobacco formulation each may undergo complete dispersion within the mouth of the user during normal conditions of use, and hence the pouch and tobacco formulation both may be ingested by the user. Other example pouch materials may be manufactured using water dispersible film forming materials (e.g., binding agents such as alginates, carboxymethylcellulose, xanthan gum, pullulan, and the like), as well as those materials in combination with materials such as ground cellulosics (e.g., fine particle size wood pulp). Preferred pouch materials, though water dispersible or dissolvable, may be designed and manufactured such that under conditions of normal use, a significant amount of the tobacco formulation contents permeate through the pouch material prior to the time that the pouch undergoes loss of its physical integrity. If desired, flavoring ingredients, disintegration aids, and other desired components, may be incorporated within, or applied to, the pouch material. In various embodiments, a nonwoven web can be used to form an outer water-permeable pouch which can be used to house a composition adapted for oral use.

The amount of material contained within each pouch may vary. In smaller embodiments, the dry weight of the material within each pouch is at least about 50 mg to about 150 mg. For a larger embodiment, the dry weight of the material within each pouch preferably does not exceed about 300 mg to about 500 mg. In some embodiments, each pouch/container may have disposed therein a flavor agent member, as described in greater detail in U.S. Pat. No. 7,861,728 to Holton, Jr. et al., which is incorporated herein by reference. If desired, other components can be contained within each pouch. For example, at least one flavored strip, piece or sheet of flavored water dispersible or water soluble material (e.g., a breath-freshening edible film type of material) may be disposed within each pouch along with or without at least one capsule. Such strips or sheets may be folded or crumpled in order to be readily incorporated within the pouch. See, for example, the types of materials and technologies set forth in U.S. Pat. Nos. 6,887,307 to Scott et al. and U.S. Pat. No. 6,923,981 to Leung et al.; and The EFSA Journal (2004) 85, 1-32; which are incorporated herein by reference.

The smokeless tobacco product can be packaged within any suitable inner packaging material and/or outer container. See also, for example, the various types of containers for smokeless types of products that are set forth in U.S. Pat. No. 7,014,039 to Henson et al.; U.S. Pat. No. 7,537,110 to Kutsch et al.; U.S. Pat. No. 7,584,843 to Kutsch et al.; D592,956 to Thiellier; D594,154 to Patel et al.; and D625,178 to Bailey et al.; US Pat. Pub. Nos. 2008/0173317 to Robinson et al.; 2009/0014343 to Clark et al.; 2009/0014450 to Bjorkholm; 2009/0250360 to Bellamah et al.; 2009/0266837 to Gelardi et al.; 2009/0223989 to Gelardi; 2009/0230003 to Thiellier; 2010/0084424 to Gelardi; and 2010/0133140 to Bailey et al; 2010/0264157 to Bailey et al.; 2011/0168712 to Bailey et al.; and 2011/0204074 to Gelardi et al., which are incorporated herein by reference.

Products of the present disclosure may be packaged and stored in much the same manner that conventional types of smokeless tobacco products are packaged and stored. For example, a plurality of packets or pouches may be contained in a container used to contain smokeless tobacco products, such as a cylindrical container sometimes referred to as a “puck”. The container can be any shape, and is not limited to cylindrical containers. Such containers may be manufactured out of any suitable material, such as metal, molded plastic, fiberboard, combinations thereof, etc. If desired, moist tobacco products (e.g., products having moisture contents of more than about 20 weight percent) may be refrigerated (e.g., at a temperature of less than about 10° C., often less than about 8° C., and sometimes less than about 5° C.). Alternatively, relatively dry tobacco products (e.g., products having moisture contents of less than about 15 weight percent) often may be stored under a relatively wide range of temperatures.

Various smokeless tobacco products disclosed herein are advantageous in that they provide a composition that is non-staining, or is staining to a lesser degree than products comprising only unwhitened tobacco materials. These products thus are desirable in reducing staining of teeth and clothing that may come in contact therewith. It is noted that even the spent (used) product is lighter in color than traditional spent (used) oral tobacco products. Further, the products may have enhanced visual appeal by virtue of their whitened color.

The following examples are provided to further illustrate embodiments of the present disclosure, but should not be construed as limiting the scope thereof. Unless otherwise noted, all parts and percentages are by weight.

Experimental

Embodiments of the present disclosure are more fully illustrated by the following examples, which are set forth to illustrate aspects of the present disclosure and are not to be construed as limiting thereof. In the following examples, g means gram, L means liter, mL means milliliter, and Da means daltons. All weight percentages are expressed on a dry basis, meaning excluding water content, unless otherwise indicated.

EXAMPLE 1

A bleached tobacco material was produced using tobacco plants as raw material. 1.1 lbs of milled N. rustica stem tobacco material (milled to a particle size of about 18-60 US mesh was soaked in 15.4 lbs of water and 2.4 g of EDTA for 1 hour. The soaked tobacco material was then pressed and drained (i.e., dewatered) using a screw press.

The drained and pressed tobacco material was then treated with a caustic wash. Specifically, 10 lbs of 2.5% NaOH was added to the pressed tobacco material. The tobacco material and caustic wash mixture was held at about 210° F. (about 100° C.) for about 90 minutes. The tobacco material in the NaOH wash was then drained and pressed to provide a tobacco pulp and residual liquid extract.

The tobacco pulp (1.34 lbs) was then mixed with a bleaching solution comprising 2L water, 15 grams NaOH, and 45 grams of sodium silicate (NaSiO₃). Next, 0.9 lbs of 35% hydrogen peroxide was added to the mixture and the mixture was cooked for 60 minutes. The cooked mixture was allowed to sit for 30 mins, and then it was neutralized with HC1 to bring the mixture to a pH of about 9. Finally the mixture was dried.

EXAMPLE 2

A bleached tobacco material was produced using tobacco plants as raw material. 1.1 lbs of finely milled burley stem tobacco material (milled to a particle size of about 18-60 US mesh) was soaked in 15.4 lbs of water and 2.4g of EDTA for 1 hour. The soaked tobacco material was then pressed and drained in a screw press.

The drained and pressed tobacco material was then treated with a caustic wash. Specifically, 10 lbs of 2.5% NaOH was added to the pressed tobacco material. The tobacco material and caustic wash mixture was held at about 210° F. (about 100° C.) for about 90 minutes. The tobacco material in the NaOH wash was then drained and pressed to provide a tobacco pulp and residual liquid extract.

The bleaching was conducted by two-stage high-consistency bleaching with peracetic acid followed by hydrogen peroxide (P). First, the pressed tobacco pulp was mixed with a first bleaching solution comprising 4.5 L of water and 50 g of peracetic acid for 90 minutes. The pH of the mixture after the addition of the peracetic acid was about 5.2. 7.0 g of NaOH was added and the new pH was about 6.8. After about 20 mins, an additional 6.0 g of NaOH was added to the mixture and the pH was about 8.0. The final pH of the tobacco pulp after the bleaching with the peracetic acid was about 8.2. The pulp was then pressed and drained in a screw press.

The tobacco pulp, bleached with peracetic acid, was then mixed with a second bleaching solution comprising 2 L water, 15 grams NaOH, 15 grams of magnesium sulfate (MgSO₄) and 45 grams of sodium silicate (NaSiO₃). Next, 0.9 lbs of 35% hydrogen peroxide was added to the mixture and the mixture was cooked for 60 minutes.

The cooked mixture was allowed to sit for 30 mins, and then it was neutralized with HCl to bring the mixture to a pH of about 9. Finally the mixture was dried.

EXAMPLE 3

A bleached tobacco material was produced using tobacco plants as raw material.

The dry weight recipe of the resulting pulp, which has no added wood pulp, is shown in Table 1 below.

TABLE 1 Recipe for Tobacco Pulp with No Wood Pulp Added Material Dry Weight Percentage Range EDTA 0.01-0.5%  Caustic Soda 20-30% Citric Acid 25-35% Sodium Silicate  0.5-2% Hydrogen Peroxide 15-20% Defoamer 0.01-0.5%  Rustica Stem 25-30%

First, tobacco biomass was extracted with hot water. About 75 lbs. of milled Rustic stem was weighed out. About 600 lbs. of hot water (about 212° F.) was added to a tank. An agitator was turned on in the tank, it was ensured that the discharge valve on the tank was closed, and the milled Rustica stem was added to the tank. Next, about 187.5 g of EDTA was weighed out and added to the tank. The steam drain on the tank was opened and steam was applied to the tank. Once the temperature of the liquid in the tank reached about 180-215° F., the contents of the tank were mixed for 50 mins while steam was still being added to the tank. After 50 minutes, the steam into the tank was cut off. The contents of the tank were then mixed for an additional 10 minutes. After mixing, the liquid in the tank was discharged and the remaining Rustica stem was rinsed and drained using a basket centrifuge. Alternative dewatering equipment can also be used. In particular, it is noted that a screw press was used for recipes that included wood pulp, while a basket centrifuge was used for recipes with no added wood pulp.

Next, the tobacco biomass was caustically extracted. About 600 lbs. of water was added to the tank. An agitator was turned on in the tank and it was ensured that the discharge valve on the tank was closed. About 37.5 lbs. of sodium hydroxide powder was measured and added to the tank. The steam drain on the tank was opened and steam was applied to the tank. Once the temperature of the liquid in the tank reached about 200-215° F., the contents of the tank were then held at about 212° F. and mixed for about 90 mins while steam was still being added to the tank. After 90 minutes, the steam into the tank was cut off. About 50.0 lbs. of citric acid powder was then measured and slowly added to the tank. The contents of the tank were then mixed for an additional 10 minutes. The pH of the contents of the tank was measured and adjusted until the pH was in the range of about 9.0 to about 10.5. After mixing, the liquid in the tank was discharged and the remaining tobacco cake was rinsed and drained using a basket centrifuge. About 100 lbs. of water can be used to rinse the residual pulp and the rinsing and dewatering steps can be repeated if necessary.

Next, the tobacco biomass was subjected to a peroxide bleaching process. The discharge valve of the tank is closed and about 600 lbs. of hot water (about 180° F.) was added to the tank. The steam drain on the tank was opened and steam was applied to the tank. The agitator for the tank was turned on. The rinsed and dewatered tobacco cake was then added to the tank. About 22.5 lbs. of sodium hydroxide powder was measured and added to the tank. About 7.5 lbs. of 40% sodium silicate was measured and added to the tank. About 127.5 lbs. of 36% peroxide was measured and added to the tank. A pump at 20 psi was run to the tank for about 1 minute with the ball valve wide open and then flushed with about 12 gallons of water. The steam drain on the tank was opened and steam was applied to the tank. Once the temperature of the liquid in the tank reached about 165° F., the liquid began to foam. About 30 grams (or more) of defoamer can be added as necessary to keep the foam contained in the tank. After the temperature of the liquid in the tank reached about 180° F., the steam was turned off and the contents of the tank were mixed for about 30-60 mins. Next, about 34.0 lbs. of citric acid powder was measured and added to the tank. The contents of the tank were then allowed to mix for about 10 minutes. The pH of the contents of the tank was then measured and adjusted until the pH was in the range of about 10.0 to about 10.75. After mixing, the liquid in the tank was discharged and the remaining tobacco cake was rinsed and drained using a screw press and/or centrifuge. About 100 lbs. of water can be used to rinse the residual pulp and the rinsing and dewatering steps can be repeated if necessary. The final tobacco cake can be dried to a moisture content of about 10-15% moisture.

EXAMPLE 4

A bleached tobacco material was produced using tobacco plants as raw material. The dry weight recipe of the resulting pulp, which has wood pulp added, is shown in Table 2 below.

TABLE 2 Recipe for Tobacco Pulp with Added Wood Pulp Material Dry Weight Percentage Range EDTA 0.01-0.5%  Caustic Soda 20-30% Citric Acid 25-35% Sodium Silicate  0.5-2% Hydrogen Peroxide 15-20% Defoamer 0.01-0.5%  Rustica Stem 25-30% Wood Pulp (Bleached Hardwood Kraft)  1-5%

The extraction and bleaching processes used above in Example 3 were also used for bleaching the tobacco biomass with the added wood pulp. However, as noted above, a screw press was used for dewatering/drying the pulp at various points in the process instead of a basket centrifuge.

EXAMPLE 5

The bleached tobacco material of Example 3 (no added wood pulp) and the bleached tobacco material of Example 4 (with added wood pulp) was tested for ISO brightness using TAPPI standardized test T 534.

Two samples of bleached tobacco pulp according to Example 3 (no added wood pulp) were tested and had an ISO brightness of 67.6% and 63.8%. One sample of bleached tobacco pulp according to Example 4 (with added wood pulp) was tested and had an ISO brightness of 70.1%.

Many modifications and other embodiments will come to mind to one skilled in the art to which this disclosure pertains having the benefit of the teachings presented in the foregoing description. Therefore, it is to be understood that the disclosure is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. 

What is claimed:
 1. A method of preparing a whitened tobacco material for use in a smokeless tobacco product, comprising: (i) extracting a tobacco material with an aqueous solution to provide a tobacco solids material and a tobacco extract; (ii) treating the tobacco solids material with a caustic wash to provide a tobacco pulp; (iii) bleaching the tobacco pulp with a solution comprising a strong base, an oxidizing agent, or a combination thereof to provide a bleached tobacco pulp; and (iv) drying the bleached tobacco pulp to provide the whitened tobacco material.
 2. The method of claim 1, further comprising milling the tobacco material such that the milled tobacco material is able to pass through a screen of 18 U.S. sieve size.
 3. The method of claim 1, wherein in the step of treating the tobacco solid material with a caustic wash is done at atmospheric pressure.
 4. The method of claim 1, wherein the caustic wash comprises at least one strong base.
 5. The method of claim 1, wherein the caustic wash comprises sodium hydroxide.
 6. The method of claim 1, wherein the bleached tobacco pulp is dried to a moisture content of less than about 30 percent moisture on a wet basis.
 7. The method of claim 1, further comprising hydrolyzing the tobacco pulp with an acid prior to step (ii).
 8. The method of claim 7, wherein the acid is sulfuric acid, hydrochloric acid, citric acid, or a combination thereof.
 9. The method of claim 1, further comprising dewatering the tobacco material using at least one of a screw press and a basket centrifuge following steps (i), (ii) and/or step (iii).
 10. The method of claim 1, wherein the bleaching step (iii) comprises treatment with one or more of peracetic acid, sodium hydroxide, and hydrogen peroxide.
 11. The method of claim 1, wherein the bleaching step (iii) further comprises treatment with one or more stabilizers in addition to an oxidizing agent.
 12. The method of claim 11, wherein the stabilizers are selected from the group consisting of magnesium sulfate, sodium silicate, and combinations thereof.
 13. The method of claim 1, wherein the bleaching step (iii) comprises treatment with a strong base and an oxidizing agent, and wherein the molar ratio of the amount of strong base to the amount of oxidizing agent is from about 1:1 to about 1:100.
 14. The method of claim 13, wherein the molar ratio of the amount of strong base to the amount of oxidizing agent is from about 1:5 to about 1:50.
 15. The method of claim 1, further comprising neutralizing the bleached pulp material to a pH in the range of about 5 to about 11 prior to step (iv).
 16. The method of claim 1, further comprising milling the whitened tobacco material following step (iv) to a size in the range of approximately 5 mm to about 0.1 mm.
 17. The method of claim 1, wherein the aqueous solution used to extract the tobacco material in step (i) comprises a chelating agent.
 18. The method of claim 17, wherein the chelating agent comprises one or more of EDTA and DTPA.
 19. The method of claim 1, wherein the molar ratio of aqueous solution to the tobacco material in the extraction step (i) is from about 4:1 to about 16:1.
 20. The method of claim 1, wherein the tobacco material comprises lamina, stems, or a combination thereof.
 21. The method of claim 1, wherein the tobacco material comprises Rustica stems.
 22. The method of claim 1, wherein the tobacco material comprises at least about 90% by weight roots, stalks, or a combination thereof.
 23. The method of claim 1, wherein the whitened tobacco material is characterized by an International Organization for Standardization (ISO) brightness of at least about 60%.
 24. The method of claim 1, further comprising mixing the tobacco solids material with a wood pulp prior to step (ii).
 25. The method of claim 1, further comprising incorporating the whitened tobacco material within a smokeless tobacco product.
 26. The method of claim 25, wherein the smokeless tobacco product further comprises one or more additional components selected from the group consisting of flavorants, fillers, binders, pH adjusters, buffering agents, colorants, disintegration aids, antioxidants, humectants, and preservatives.
 27. A smokeless tobacco product incorporating the whitened tobacco material prepared according to the method of claim
 1. 28. The smokeless tobacco product of claim 27, comprising a water-permeable pouch containing the whitened tobacco material.
 29. The smokeless tobacco product of claim 27, further comprising one or more additional components selected from the group consisting of flavorants, fillers, binders, pH adjusters, buffering agents, colorants, disintegration aids, antioxidants, humectants, and preservatives. 